Prolongs fossil fuel supplies Solutions Solutions Reducing Energy Waste Reducing Energy Waste Prolongs fossil fuel supplies Reduces oil imports Very high net energy Low cost Reduces pollution and environmental degradation Buys time to phase in renewable energy Less need for military protection of Middle East oil resources Improves local economy by reducing flow of money out to pay for energy Creates local jobs Figure 18-2 Page 380

Nonrenewable fossil fuels Useful energy Energy Inputs System Outputs 9% 7% 41% 86% U.S. economy and lifestyles 43% 8% 3% 3% Nonrenewable fossil fuels Useful energy Petrochemicals Nonrenewable nuclear Unavoidable energy waste Hydropower, geothermal, wind, solar Figure 18-3 Page 381 Unnecessary energy waste Biomass

Index of energy use per capita and per dollar of GDP (Index: 1970=1) 1.4 1.2 Energy use per capita 1.0 Index of energy use per capita and per dollar of GDP (Index: 1970=1) 0.8 0.6 0.4 Energy use per dollar of GDP 0.2 1970 1980 1990 2000 2010 2020 Figure 18-4 Page 381 Year

H2 O2 H2O KOH Fuel cell Figure 18-5a Page 381 45-65%

Steam turbine Figure 18-5b Page 381 45%

Human body Figure 18-5c Page 381 20–25%

Fluorescent light Figure 18-5d Page 381 22%

Internal combustion engine Figure 18-5e Page 381 (gasoline) 20-25%

Incandescent light Figure 18-5f Page 381 5%

Stepped Art Figure 18-6 Page 382 95% Waste heat Uranium mining (95%) 54% Waste heat Uranium processing and transportation (57%) 17% Waste heat Power plant (31%) Waste heat 14% Transmission of electricity (85%) 14% Resistance heating (100%) Uranium 100% Electricity from Nuclear Power Plant Window transmission (90%) Passive Solar Sunlight 100% 90% Waste heat Stepped Art Figure 18-6 Page 382

(miles per gallon, or mpg) 30 25 Cars (miles per gallon, or mpg) Average fuel economy 20 Both 15 Pickups, vans, and sport utility vehicles 10 1970 1975 1980 1985 1990 1995 2000 2005 Model Year Figure 18-7 Page 383

Dollars per gallon (in 1993 dollars) 2.2 2.0 1.8 1.6 Dollars per gallon (in 1993 dollars) 1.4 1.2 1.0 0.8 Figure 18-8 Page 383 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Year

A C B D E F Combustion engine Electric motor Fuel tank Battery bank Small, efficient internal combustion engine powers vehicle with low emissions. A Electric motor Traction drive provides additional power, recovers breaking energy to recharge battery. C Fuel tank Liquid fuel such as gasoline, diesel, or ethanol runs small combustion engine. B Battery bank High-density batteries power electric Motor for increased power. D Regulator Controls flow of power between electric Motor and battery pack. E B Transmission Efficient 5-speed automatic transmission. F D E F A C Figure 18-9 Page 385 Fuel Electricity

Cell splits H2 into protons and electrons. Protons flow Hydrogen gas 1 Cell splits H2 into protons and electrons. Protons flow across catalyst membrane. 3 1 O2 2 React with oxygen (O2). 2 3 Produce electrical energy (flow of electrons) to power car. 4 H2O 4 Emits water (H2O) vapor. Figure 18-10a Page 385

A B C D E Fuel Electricity Fuel tank Fuel cell stack Turbo compressor Hydrogen and oxygen combine chemically to produce electricity. B Fuel tank Hydrogen gas or liquid or solid metal hydride stored on board or made from gasoline or methanol. C Turbo compressor Sends pressurized air to fuel cell. D Traction inverter Module converts DC electricity from fuel cell to AC for use in electric motors. B E Electric motor/transaxle Converts electrical energy to mechanical energy to turn wheels. D C E A Figure 18-10b Page 385 Fuel Electricity

Universal docking connection Connects the chassis with the Drive-by-wire system in the body Body attachments Mechanical locks that secure the body to the chassis Rear crush zone absorbs crash energy Fuel-cell stack Converts hydrogen fuel into electricity Air system management Drive-by-wire system controls Cabin heating unit Side mounted radiators Release heat generated by the fuel cell, vehicle electronics, and wheel motors Front crush zone Absorbs crash energy Hydrogen fuel tanks Electric wheel motors Provide four-wheel drive Have built-in brakes Figure 18-11a Page 386

Figure 18-11b Page 386

R-60 or higher insulation R-30 to R-43 insulation Small or no north-facing windows or superwindows Insulated glass, triple-paned or superwindows (passive solar gain) R-30 to R-43 insulation House nearly airtight R-30 to R-43 insulation Air-to-air heat exchanger Figure 18-12 Page 387

DO NOT POST TO INTERNET Figure 18-13 Page 387

DO NOT POST TO INTERNET Figure 18-14 Page 388

Figure 18-15 Page 389 Net Energy Efficiency Superinsulated house(100% of heat R-43) 98% Geothermal heat pumps (100% of heating and cooling)) 96% Passive solar (100% of heat) 90% Passive solar (50% of heat) plus high- efficiency natural gas furnace(50% of heat) 87% Natural gas with high-efficiency furnace 84% Electric resistance heating (electricity from hydroelectric power plant) 82% Natural gas with typical furnace 70% Passive solar (50% of heat) plus high-efficiency wood stove (50% of heat) 65% Oil furnace 53% Electric heat pump (electricity from coal-fired power plant) 50% High-efficiency wood stove 39% Active solar 35% Electric heat pump (electricity from nuclear plant) 30% Typical wood stove 26% Electric resistance heating (electricity from coal-fired power plant) 25% Electric resistance heating (electricity from nuclear plant) 14% Figure 18-15 Page 389

Summer sun Heavy insulation Superwindow Winter Superwindow sun Stone floor and wall for heat storage Figure 18-16a Page 389 PASSIVE

Heat to house (radiators or forced air duct) Pump Heavy insulation Hot water tank Super- window Heat exchanger Figure 18-16b Page 389 ACTIVE

Direct Gain Ceiling and north wall heavily insulated Hot air Super Summer sun Hot air Super insulated windows Winter sun Warm air Cool air Earth tubes Figure 18-17a Page 392

Greenhouse, Sunspace, or Attached Solarium Summer cooling vent Warm air Insulated windows Cool air Figure 18-17b Page 392

carefully waterproofed walls and roof Earth Triple-paned or Earth Sheltered Reinforced concrete, carefully waterproofed walls and roof Earth Triple-paned or superwindows Flagstone floor for heat storage Figure 18-17c Page 392

Passive or Active Solar Heating Trade-offs Passive or Active Solar Heating Advantages Disadvantages Energy is free Net energy is moderate (active) to high (passive) Quick installation No CO2 emissions Very low air and water pollution Very low land disturbance (built into roof or window) Moderate cost (passive) Need access to sun 60% of time Blockage of sun access by other structures Need heat storage system High cost (active) Active system needs maintenance and repair Active collectors unattractive Figure 18-18 Page 392

Solar Energy for High-Temperature Trade-Offs Solar Energy for High-Temperature Heat and Electricity Advantages Disadvantages Moderate net energy Moderate environmental Impact No CO2 emissions Fast construction (1-2 years) Costs reduced with natural gas turbine backup Low efficiency High costs Needs backup or storage system Need access to sun most of the time High land use May disturb desert areas Figure 18-19 Page 393

Single Solar Cell Boron-enriched Sunlight silicon Junction Cell Phosphorus- enriched silicon DC electricity Figure 18-20a Page 394

Roof Options Panels of Solar Cells Solar Cells Figure 18-20b Page 394

Solar Cell Roof Figure 18-20c Page 394

Trade-Offs Solar Cells Advantages Disadvantages Fairly high net energy Work on cloudy days Quick installation Easily expanded or moved No CO2 emissions Low environmental impact Last 20-40 years Low land use (if on roof or built into walls or windows) Reduce dependence on fossil fuels Need access to sun Low efficiency Need electricity storage system or backup High land use (solar cell power plants) could disrupt desert areas High costs (but should be competitive in 5-15 years) DC current must be converted to AC Figure 18-21 Page 395

Large-Scale Hydropower Trade-Offs Large-Scale Hydropower Advantages Disadvantages Moderate to high net energy High efficiency (80%) Large untapped potential Low-cost electricity Long life span No CO2 emissions during operation May provide flood control below dam Provides water for year-round irrigation of crop land Reservoir is useful for fishing and recreation High construction costs High environmental impact from flooding land to form a reservoir High CO2 emissions from biomass decay in shallow tropical reservoirs Floods natural areas behind dam Converts land habitat to lake habitat Danger of collapse Uproots people Decreases fish harvest below dam Decreases flow of natural fertilizer (silt) to land below dam Figure 18-22 Page 396

Gearbox Electrical generator Power cable Wind Turbine Figure 18-23a Page 396 Wind Turbine

Figure 18-23b Page 396 Wind Farm

Trade-Offs Wind Power Advantages Disadvantages Moderate to high net energy High efficiency Moderate capital cost Low electricity cost (and falling) Very low environmental impact No CO2 emissions Quick construction Easily expanded Land below turbines can be used to grow crops or graze livestock Steady winds needed Backup systems when needed winds are low High land use for wind farm Visual pollution Noise when located near populated areas May interfere in flights of migratory birds and kill birds of prey Figure 18-24 Page 397

Gaseous Biofuels Liquid Biofuels Figure 18-25 Page 398 Solid Biomass Fuels Wood logs and pellets Charcoal Agricultural waste (stalks and other plant debris) Timbering wastes (branches, treetops, and wood chips) Animal wastes (dung) Aquatic plants (kelp and water hyacinths) Urban wastes (paper, cardboard, and other combustible materials) Direct burning Conversion to gaseous and liquid biofuels Gaseous Biofuels Synthetic natural gas(biogas) Wood gas Liquid Biofuels Ethanol Methanol Gasohol Figure 18-25 Page 398

Trade-Offs Solid Biomass Advantages Disadvantages Large potential supply in some areas Moderate costs No net CO2 increase if harvested and burned sustainably Plantation can be located on semiarid land not needed for crops Plantation can help restore degraded lands Can make use of agricultural, timber, and urban wastes Nonrenewable if harvested unsustainably Moderate to high environmental impact CO2 emissions if harvested and burned unsustainably Low photosynthetic efficiency Soil erosion, water pollution, and loss of wildlife habitat Plantations could compete with cropland Often burned in inefficient and polluting open fires and stoves Figure 18-26 Page 399

Trade-Offs Ethanol Fuel Advantages Disadvantages High octane Some reduction in CO2 emission Reduced CO emissions Can be sold as gasohol Potentially renewable Large fuel tank needed Lower driving range Net energy loss Much higher cost Corn supply limited May compete with growing food on cropland Higher NO emission Corrosive Hard to start in colder weather Figure 18-27 Page 399

Trade-Offs Methanol Fuel Advantages Disadvantages High octane Some reduction in CO2 emissions Lower total air Pollution (30-40%) Can be made from natural gas, agricultural wastes, sewage sludge, and garbage Can be used to produce H2 for fuel cells Large fuel tank needed Half the driving range Corrodes metal, rubber, plastic High CO2 emissions if made from coal Expensive to produce Hard to start in cold weather Figure 18-28 Page 400

Trade-Offs Geothermal Fuel Advantages Disadvantages Very high efficiency Moderate net energy at accessible sites Lower CO2 emissions than fossil fuels Low cost at favorable sites Low land use Low land disturbance Moderate environmental impact Scarcity of suitable sites Depleted if used too rapidly CO2 emissions Moderate to high local air pollution Noise and odor (H2S) Cost too high except at the most concentrated and accessible source Figure 18-29 Page 401

Can be produced from plentiful water Low environmental impact Trade-Offs Hydrogen Advantages Disadvantages Can be produced from plentiful water Low environmental impact Renewable if produced From renewable energy resources No CO2 emissions if produced from water Good substitute for oil Competitive price if environmental and social costs are included in cost comparisons Easier to store than electricity Safer than gasoline and natural gas Nontoxic High efficiency (65-95%) in fuel cells Not found in nature Energy is needed to produce fuel Negative net energy CO2 emissions if produced from carbon-containing compounds Nonrenewable if generated by fossil fuels or nuclear power High costs (but expected to come down) Will take 25 to 50 years to phase in Short driving range for current fuel cell cars No distribution system in place Excessive H2 leaks may deplete ozone Figure 18-30 Page 401

Primary Energy Sources Electricity Generation Commercial/Residential Sunlight Fossil fuels Biomass Wind Photo-conversion Electrolysis Reforming Hydrogen Production Electricity Generation Transport Vehicles and pipeline Storage Gas and solids Utilization Electric utility Transportation Commercial/Residential Industrial Figure 18-31 Page 403

Fuel cells Commercial Residential Industrial Microturbines Bioenergy Power plants Wind farm Small solar cell power plants Fuel cells Rooftop solar cell arrays Solar cell rooftop systems Transmission and distribution system Small wind turbine Commercial Residential Industrial Figure 18-32 Page 405 Microturbines

Small modular units Fast factory production Fast installation (hours to days) Can add or remove modules as needed High energy efficiency (60–80%) Low or no CO2 emissions Low air pollution emissions Reliable Easy to repair Much less vulnerable to power outages Increase national security by dispersal of targets Useful anywhere Especially useful in rural areas in developing countries with no power Can use locally available renewable energy resources Easily financed (costs included in mortgage and commercial loan) Figure 18-33 Page 406

$73 billion Nuclear energy (fission and fusion) $32 billion Fossil fuels $19 billion Renewable energy Energy efficiency (conservation) $15 billion Figure 18-34 Page 407

Improve Energy Efficiency More Renewable Energy Increase renewable energy to 20% by 2020 and 50% by 2050 Increase fuel-efficiency standards for vehicles, buildings, and appliances Provide large subsidies and tax credits for renewable energy Use full-cost accounting and life cycle cost for comparing all energy alternatives Mandate government purchases of efficient vehicles and other devices Encourage government purchase of renewable energy devices Provide large tax credits for buying efficient cars, houses, and appliances Greatly increase renewable energy research and development Offer large tax credits for investments in efficiency Reduce Pollution and Health Risk Reward utilities for reducing demand Cut coal use 50% by 2020 Phase out coal subsidies Encourage independent power producers Levy taxes on coal and oil use Phase out nuclear power or put it on hold until 2020 Greatly increase efficiency research and development Phase out nuclear power subsidies Figure 18-35 Page 407

Use mass transit, walking, and bicycling. What Can You Do? Energy Use ad Waste Drive a car that gets at least 15 kilometers per liter (35 miles per gallon) and join a carpool. Use mass transit, walking, and bicycling. Superinsulate your house and plug all air leaks. Turn off lights, TV sets, computers, and other electronic equipment when they are not in use. Wash laundry in warm or cold water. Use passive solar heating. For cooling, open windows and use ceiling fans or whole-house attic or window fans. Turn thermostats down in winter and up in summer. Buy the most energy-efficient homes, lights, cars, and appliances available. Turn down the thermostat on water heaters to 43-49ºC (110-120ºF) and insulate hot water heaters and pipes. Figure 18-36 Page 408